Enzymatic direct carboxylation under supercritical CO2

Thermodynamically-constrained carboxylation reaction requires high temperature and pressure in industrial processes. Research endeavors are aimed towards developing safer and greener alternatives. Enzymatic systems are considered as potential substitutes. In this study, we conducted direct carboxylation via a bi-enzymatic reaction with Thermoplasma acidophilum isocitrate dehydrogenase (TaIDH) and T. acidophilum glucose dehydrogenase (TaGDH) to produce isocitric acid from of 2-ketoglutaric acid under supercritical CO2. Coupling with the TaGDH reaction (for cofactor regeneration) enabled the equilibrium of the reactions to shift towards carboxylation, resulting in a 16-fold increase in yield. Furthermore, the yield was increased by optimizing the reaction parameters such as pH, substrate concentration, temperature, and time, and by testing various metal ions. A preparative scale reaction was conducted successfully.

Automated summary

The study achieved carboxylation through enzymatic reaction under specific conditions, resulting in increased yield.